Capability

Broadly speaking, capability is the ability to reach a certain level of
performance. This includes the capability of processes, people and IT in
the whole system of performance and delivery.

If you promise what customers want, but do not have the capability to
deliver it, then you are planning to fail. It is a major part of the
quality job to ensure that the organization has the capability to meet its
goals. For most quality folks, this has a process focus, but as processes
cannot be separated from the people and other systems, it should be a
collaborative effort with HR, IT and so on.

Process capability around a numerically measurable process has a more
precise definition and in SPC, the Capability Index, Cpk is a process measure of the spread of
performance measures in comparison with given performance limits. Cmk
is Machine Capability or Short-term Capability.